We aim to produce non-racemic biologically active molecules by employing optically active organometallic nucleophiles in transition metal-catalyzed carbon-carbon bond- forming reactions. By establishing the stereogenic center prior to the formation of the final desired bond, the rapid preparation of diverse libraries of single-enantiomer drug candidates for use in biologic assays will be achievable. The use of optically active secondary nucleophiles will be initially explored in alkyl-aryl cross-coupling reactions, an extended to the use of optically active tertiary nucleophiles. Alkylboron and alkyl azastannatrane reagents constitute the main nucleophiles involved in this study. Although the major focus of this work is on palladium- and nickel-catalyzed systems, the use of copper and silver catalysis will also be investigated. Our stereoretentive cross- coupling reactions will be extended to the construction of carbon-heteroatom bonds in order to maximize access to chiral structural motifs that are currently inaccessible but are of biological or pharmaceutical interest.